There is a general tendency for wire-harnesses to become large in size in correspondence with electronic devices increasingly used in recent automobiles. In order to keep such a wire-harness compact, multiple wiring systems for the wire-harness have been developed, and particularly it has been proposed that the insulated or coated wire for the wire-harness must be compact in size.
On the other hand, the automatic assembling of the wire-harness having jumbled wires due to a complex circuit arrangement has been developed, for example, a system in which a wire is terminated in a slotted terminal without the use of crimping which is a typical conventional way to connect the wire to the terminal.
In a conventional structure to connect a wire to the slotted terminal, the slotted terminal comprises a terminal contact portion integrally formed with a wire connecting portion having a slotted opening having a width less than the diameter of the wire. In addition, a tinned, twisted concentric wire or an integrally tinned wire is used for the coated wire in the conventional structure.
The term "twisted concentric wire" is used herein to mean a plurality of individual strands about a central core strand in a concentric array which are helically stranded or twisted.
The term "integrally tinned wire" is used herein to mean a plurality of individual strands integrally bundled through tinning.
When the twisted concentric wire is connected to the slotted terminal, the wire is inclined to be deformed, resulting in variance in connecting operation, so that it is not easy to produce completely reliable connection with this wire.
When the integrally tinned wire is connected to the slotted terminal, the integrity in shape of the wire inserted in the wire connecting portion is kept, thereby providing excellent electric connection. However, since the wire of this type is insufficient in flexibility, it is not easy to incorporate such a wire-harness having the wire of this type into a vehicle and in addition, the wire sometimes breaks due to vibrations in use.